I've been learning and incorporating pentatonic scales into my playing and have found them great for runs and fills (rock/pop/folk). However, there's something I can't quite figure out... When do you use the pentatonic scale of the key vs. the pentatonic scale of the root/chord??? For example. Say you've got a simple I-IV-V progression in C with a fill between the IV going to the V. Would I use the C, F, or G pentatonic moving from the F chord to the G chord??? I hope this makes sense. Sometimes one way seems to work and other times it doesn't.